A drive device of an automatic ice machine mounted in a domestic electric refrigerator disclosed in Patent Laid Open 2001-272146 automatically supplies water on an ice tray disposed in a refrigeration room, and after frozen, discharges ice from the ice tray by the drive device.
FIG. 6 is a plan view showing the drive device of an existing automatic ice machine. The existing device is composed of (i) ice tray 1 of storing water and making ice, (ii) a plurality of fixing fingers 2 making fixed rows on the upper face of ice tray 1, (iii) moving pawls 3 rotating by a motor (not shown) and discharging ice, (iv) stop arm 4 of detecting an amount of ice storing in an ice box (not shown), and (v) control box 5 of working moving pawls 3 and stop arm 4.
Ice tray 1 includes a thermister and a heater. When water in ice tray 1 is frozen, and the thermister detects completion of making ice, the heater is electrically conducted. When ice begins melting at an ice surface contacting ice tray 1, the electric conduction to heater 1 is finished, and subsequently the conduction to the motor begins. When moving pawl 3 is rotated 360° by rotation of the motor, ice in ice tray 1 is discharged. The discharged ice is sent to the ice box. After moving pawls 3 are rotated 360°, ice tray 1 is supplied with water, and again the ice making work is started. The above work is repeated until stop arm 4 detects predetermined amount of ice.
However, in the drive device of the existing automatic ice machine, since ice is easily removed from the ice tray, ice shapes are uniformly rounded. Less round and rock like ice cannot be made, which is demanded by consumers.